code: def forward(
      self, tgt, memory, tgt_mask=None, memory_mask=None, cache=None
  ):
      residual = tgt
      if self.normalize_before:
          tgt = self.norm1(tgt)
      if cache is None:
          tgt = self.self_attn(tgt, tgt, tgt, tgt_mask, None)
      else:
          tgt, incremental_cache = self.self_attn(
              tgt, tgt, tgt, tgt_mask, cache[0]
          )
      tgt = residual + self.dropout1(tgt)
      if not self.normalize_before:
          tgt = self.norm1(tgt)
  
      residual = tgt
      if self.normalize_before:
          tgt = self.norm2(tgt)
      if len(memory) == 1:
          # Full sent
          tgt = self.cross_attn(
              tgt, memory[0], memory[0], memory_mask, None
          )
      else:
          # Wait-k policy
          cross_attn_outputs = []
          for i in range(tgt.shape[1]):
              q = tgt[:, i : i + 1, :]
              if i >= len(memory):
                  e = memory[-1]
              else:
                  e = memory[i]
              cross_attn_outputs.append(
                  self.cross_attn(
                      q,
                      e,
                      e,
                      memory_mask[:, :, i : i + 1, : e.shape[1]],
                      None,
                  )
              )
          tgt = paddle.concat(cross_attn_outputs, axis=1)
      tgt = residual + self.dropout2(tgt)
      if not self.normalize_before:
          tgt = self.norm2(tgt)
  
      residual = tgt
      if self.normalize_before:
          tgt = self.norm3(tgt)
      tgt = self.linear2(
          self.dropout(self.activation(self.linear1(tgt)))
      )
      tgt = residual + self.dropout3(tgt)
      if not self.normalize_before:
          tgt = self.norm3(tgt)
      return tgt if cache is None else (tgt, (incremental_cache,))
  
file_path: PaddleHub/modules/text/simultaneous_translation/stacl/transformer_nist_wait_7/model.py
imports: import numpy
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddlenlp.transformers import WordEmbedding, PositionalEmbedding
label_desc: Use image node_id 2 for calling the DecoderLayer obj's underlying member method code with example usage: obj.forward(tgt, memory, tgt_mask, memory_mask, cache) and returns: unknown